This invention relates to a filter and to a method of using the filter to remove particulates from a fluid stream. More particularly, this invention relates to a filter composed of one or more plates each having at least one specially configured primary fluid passage and at least one particulate-collecting chamber on the surface thereof, the particulate-collecting chamber being capable of generating eddy currents which remove particulates from the fluid stream passing through the filter.
Conventional filters for removing particulate matter from fluid streams have drawbacks. For example, conventional filters tend to be bulky, which makes them expensive to make and use and difficult to clean and re-use. Furthermore, in conventional filters, particulates are typically trapped in a web of fibers or other three-dimensional material having tiny pores. These pores eventually become clogged with the trapped particulates, leading to an increased pressure drop across the filter and eventual impedance or blockage of fluid flow through the filter.
It would be desirable, therefore, to provide a filter for removing particulates from fluid streams which does not operate to trap the particulates in a web or other material having tiny pores.
Alternative filters are known in the art for separating particulates from fluid streams. For example, filters capable of producing eddy currents to separate particulate matter from fluid streams are known. Reference is made, for example, to U.S. Pat. Nos. 4,156,644 (to Richard) and 3,925,205 (to Sparham). The filter disclosed in the Richard patent is a sludge bed in which preferential currents are formed. These currents promote agglomeration of the sludge while allowing contaminated liquid to flow upwardly through the sludge bed at a relatively high rate. The preferential currents are formed in the sludge bed by a flow control system, which can be composed of inclined, corrugated metal plates. Baffles on these plates produce eddy effects in the preferential currents. Sparham discloses a method of separating solids suspended in a liquid, wherein the liquid is passed through a labyrinth of eddy-forming surfaces in series with a sheet perforate member. The labyrinth may be composed of metallic plate-like members having eddy-forming surfaces. The eddy-forming surfaces may be in the form of ribbed walls or an undulating cross-section. The liquid passes through passages (which follow a zig-zag or non-linear path) formed between the plate-like members.
In the filters disclosed in the Richard and Sparham patents, the particulate-collecting regions are situated in the primary or main flow path of the fluid stream passing through the filters. As a result, particulates filtered from the fluid stream accumulate in the primary flow path and eventually impede or block fluid flow through the path. Thus, like the conventional filters discussed previously herein, the Richard and Sparham filters also experience flow blockage. Therefore, it would be desirable to provide a filter for removing particulates from a fluid stream wherein the particulate-collecting region of the filter is not situated in the primary flow path, and the accumulation of particulates in these regions does not operate to impede or block the flow of the fluid through the filter.
A primary object of this invention is to provide a filter having one or more particulate-collecting chambers, wherein the particulate-collecting chamber(s) is not situated in the primary flow path of the primary fluid flow passage and particulate accumulation into these particulate-collecting chamber(s) does not impede or block fluid flow through the filter or increase pressure drop across the filter.
Another object of this invention is to provide a filter for removing particulates from a fluid stream, wherein the filter is relatively easy and inexpensive to manufacture, clean, inspect, re-use, dispose of, and replace.
An additional object of this invention is to provide a method of removing particulates from a fluid stream comprising the use of a filter having the characteristics set forth in the preceding objects.
These and other objects which are achieved according to the present invention can be readily discerned from the following description.